When serum B12 results are equivocal or clinical suspicion remains high despite normal B12 levels, additional tests may be requested: Methylmalonic acid (MMA) : Elevated levels indicate functional B12 deficiency at the cellular level, though availability may be limited in primary care and levels can be elevated in renal impairment Homocysteine : Also elevated in B12 deficiency, though less specific and also affected by renal function Intrinsic factor antibodies : To investigate pernicious anaemia, the most common cause of B12 deficiency in the UK Anti-parietal cell antibodies : May be tested if pernicious anaemia is suspected but intrinsic factor antibodies are negative Identifying the underlying cause is crucial for appropriate management
Xu and Yadan (1995) reported the synthesis of EGT from L-histidine via an N , N -dimethyl imidazole- 2-thione derivative in six steps, with an overall yield of 34% (Scheme 1a)
Flanagan, S
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Over an entire vial, the cumulative dead space can mean your last dose comes up slightly short
The LODs for N-Hcy-Lys and low-molecular-mass thiols (Hcy, GSH, Cys) in plasma samples were 0.08 and 0.1 nmol/mL, respectively, while LOQs were 0.10 and 0.15 nmol/mL, respectively